The present invention is directed to a system for cooling electronic components and the like. More particularly, the invention is directed to such a system which comprises a number of graphitic foam heat exchangers that are each thermally coupled to a corresponding electronic component and a conduit network for communicating a cooling fluid from a fluid source to each graphitic foam heat exchanger.
Existing devices for cooling electronic components include aluminum and copper heat sinks, which are attached to the component and rely on natural or forced convection to remove the heat from the component. Although aluminum and copper have good thermal conductivities in general, the specific thermal conductivity of each of these materials, that is, the thermal conductivity divided by the specific gravity of the material, is only around 50 W/m-K. Therefore, such heat sinks are generally suitable only for relatively low power components which do not generate significant amounts of heat. For higher power electronic components, the above-described heat sinks have been combined with cooling loops through which a cooling fluid is circulated to more effectively remove the heat generated by the component. However, a risk exists that such a device will leak and damage the component.
In recent years graphitic foam products have been developed for use as heat sinks for electronic components. These graphitic foam products have an open microcellular structure which is defined by an interconnected network of highly aligned graphitic ligaments. As a result, they have very low densities yet relatively high thermal conductivities. Consequently, such foams can have specific thermal conductivities of 300 W/m-K or greater, which is significantly larger than many other thermal management materials.
In addition, researchers at the Oak Ridge National Laboratory have developed a highly efficient heat exchanger which employs a graphitic foam product as the heat transfer medium between an electronic component and a cooling fluid. As described in an article by Klett et al. entitled, “Graphitic Foam Thermal Management Materials for Electronic Packaging” (Copyright© 2000 Society of Automotive Engineers, Inc.), this heat exchanger comprises a graphite foam block which is enclosed in an aluminum housing that forms a substrate for the electronic component. In operation, cool air is forced through the housing and the foam block to remove the heat generated by the component.
Many devices, such as computer workstations and servers, comprise a number of electronic components which each require cooling. However, each of the above-described heat exchangers is typically capable of cooling only a single component. Moreover, although a system of multiple such heat exchangers could be provided to cool all of the components of a single device, such a system would likely require a corresponding number of fluid sources. The existence of multiple fluid sources in a heat exchanger system would undoubtedly make the system both complicated and expensive. Therefore, a need exists for a simple heat exchanger system which is capable of cooling a number of electronic components in a single device.